Rolf,
When I first started making my own sails back in the 80s. I only had brass eyelets.

As you say, they are not strong enough by themselves.
So I cut a very short length of stainless tube whose OD just fitted the ID of the eyelet. I then used the rounded head of the tool I put the eyelet in with to turn the edges over to make a stainless insert for the brass eyelet and that worked fine. So for anyone who is making a sail and can only source brass it may be an option.

Regards,
Phill

I know that the voices in my head aint real,
but they have some pretty good ideas.
There is no such thing as a quick fix and I've never had free lunch!